Technical Unsprung Weight Issues In Hot Rods: School Me

Cool! Glad it worked out well, and thanks for coming back on and reporting the results (with pics even, yeay!)

 

My roadster is a Deuce Brookville highboy with an 8"Maverick V-8 rear, 700R-4, Vortek 350, Chassis Engineering, 4" dropped forged axle. My problem is the steelie wheels, 15X5 front but 15X10 on rear with Hoosier 31x12.50x15 radials. I think these rear steelies/tires weight as much as I do and I'm looking for a shitty-looking mag like 15x6 or 7 to lighten up that ass. I will run moon discs all around to cover the ugly mags and maybe will have a better ride. I really love the look of the huge tires but we are willing to downsize just so we can drive further than 300 miles a day when we cross-country cruise. Shouldn't this reduction in unsprung weight help the ride ?

 

A tube axle and hairpins ? This puts a new slant on "rigidity". You cured lots of problems with the addition of the 4-bar setup.

 

Gary Addcox
Try reducing the tire pressure in the rear tires, to 25.
Check condition of rear shocks.
Both affect rear suspension effectiveness.


Phil

 

Just a side note:

The car rides and drives very well now...most of the time. But at one point in this thread 31vicky with a hemi made mention of the GM 12-bolt rear axle with steel wheels and dirt track tires being too heavy for this application. Excess unsprung weight.

Well, now that the front end is tamed down the beating the rear of the car takes going over big bumps has become very noticeable. Somebody else said that it's like beating on the bottom of the car with a big hammer. I'm just here to tell you that it's all true.

But that's another issue for another time...

 

There you go,

 

Save your money, Hoosier is 39#. A steel belted 275/60 is 36#. Wheels are also a wash. M/T 275/60 is 31#.

 

Fill the tires with helium and the car will float over the bumps.

 

A guy goes to the doctor because he's having problems with his sex life. The doctor tells him that he's 40 lbs overweight, his celestial is too high, his blood pressure is too high, he smokes too much,he drinks too much. he doesn't exercise.
The guy responds to the doctor. Thats not my problem, I just need Viagra.

 

And those may not have been his problems, he might have just had an ugly wife...

But my point is that here on the HAMB everybody is a "doctor", but not too many of 'em know what they're talking about. In my humble opinion it's ALWAYS best to question EVERYBODY'S advice until you are satisfied that the information you're using to make your decision is sound and wise. Sometimes that means rejecting at first what later turns out to be true. In this case it took me a while to separate the good advice from the bad, but I finally got there and the car is much much better now. Thanks for your comment.

 

I just went through this whole thread quickly.
One thing I don't think was mentioned was shackle angle's impact on the spring's ability work properly.
I see in the recent pictures you changed perches, I assume the spring is the same spring.
You did your self a big favor, and probably don't know it.
You front shackle is now at a much better angle, & will allow the spring to work.
Some spring manufacturers make their springs so short the shackles are almost straight out to the side.
This keeps the spring from being able work, & makes things stiff.
I'll bet some of your original problem came from the bad shackle angle.
I'm posting a picture of your original shackle angle . . . it wasn't good . .



This new angle is much better

 

Thanks for taking the time to review this thread and offer your input, Pete. I changed to the adjustable perches primarily to improve what looked to be a slight bind condition in the shackles but honestly never considered that the shackle angle might be wrong. Glad to hear that my change was a good one even though it was accidental as you suspected. Thanks again for the review.

 

We've been getting quite heavily into that subject on this thread: https://www.jalopyjournal.com/forum/threads/tranverse-springs-tech-info.1112840/ It'd be good to have your input, too.

 

Yes.

 

Eric it looks like you got the best advice from Pwood..
Are you running Bias Ply Tires on the Front? I got the new plates for my roadster.
PM me Frank

 

Yes, the front tires are Firestone ribbed dirt trackers from Coker. They do have some minor roundness issues which I am willing to put up with for the look. I'm also willing to put up with the unsprung weight issue in the rear for the time being, I'll just always keep the gas tank full.

 

I just read Pete Eastwood's comment on shackle angle. My situation is the opposite on my rear spring - the shackles are almost vertical. Good or not?

 

Tube axle with split wish bones , not a good .
I run three leafs on front with good shocks. Same brakes you are running .I beam axle.
Stock 32 rear spring three leafs p&j shocks on rear.
Car rides and handles like a sports car.

 

Tube axle and hair pins with a mustang box just doesn't work ,
Mustang box good for 4 bar setup.

 

correction i run 4 leafs front and rear.

 

You will have to carry a helium bottle with you, because the tires won't hold the air for long. Helium goes through almost everything.
Bob